Manufacture of stencils for duplicating apparatus



sanctum, 1926.

" UNITED STATES PATENT O FICE.

rnoncmrron, or vrrn -sonrsnmn, rnnnon, ASSIGNOR co m :B. incx comment, or omcneo, ILLmOIs, A CORPORATION OF ILLINOIS.

ILANUFAGTUBE OF STENCILS FOR DUPLICATING APTARA'IUS.

Io Drawing. Original application filed December 12, 1921, Serial NO. 521,868, and in Belgium December 22, 1920. Divided and this application filed October 15, 1923. Serial No. 668,767.

Thisiinvention relates to the manuiacture of stencils i'or duplicating apparatus and it has more particularly for its b ectto provide an improved process for the manu-' facture of such stencils which will afi'ord considerable advantages compared with the processes employed hitherto, as will be perceived from the following description. My present application is a 'division of my api0 'plication berial N 0. 521,866, filed December 12, 1921, manufacture of stencils for duplicating apparatus.

Stencils as employed hitherto have, as a ,matter of tact,'the following drawbacks i 1. A paraffin-coated stencil allows the duplicating ink to pass through the cracks that are caused accidentally either through the usual handling, or by the stencil being carried along by the typewriting machine in which it is being used, at the instant when it is being impressed by the matter that is to be duplicated. Such cracks give rise to ink spots on the copies.

'2. Other kinds of stencils are not subject e to the occurrence of the cracks referred to under 1, but they have to be moistened before being used in the typewriter". This moistening operation has as its chief drawback, that of causing the parts of the type- 50 writer to become moistened as well,--with consequent rusting and deterioration of those parts. A stencil of that kind is not sufliciently thick (that is, has not su'fiicient body) and is diificult to keep in correct position on the inking cylinders of rotary and other duplicating machines so that the matter on the stencil is not adapted to produce uniform copies.

The above-mentioned drawbacks are ob- 40 viated by the present invention which consists broadly in using as the stencil a sheet of Japanese paper (such as is already in general use in this class of manufacture and commonly known as Yoshino) impregnated uniformly with pharmaceutical or industrial collodion, or a solution of celluloid with an addition of castor oil, and coated on one side with a coat of parafiin, ceresine wax, or generally with a coat of a solidifiable fatty min eral, vegetable or animal substance.

This last coat is intended'to maintain in a supple condition the collodion or solution of celluloid with which the sheet is impreghated; it also serves as a cushion or resilient underlay for facilitating the stencilizing 5g, of the coat of collodion or solution of celluloid by' the type characters of the typewriter.

It is to be noted that with this object in view the typing should be done on that side so oi the sheet that is not coated with paraifin.

As a. bath having a celluloid basis there may be used a suitable solution of this latter substance in one of its. solvents, or in several of these together, such as ether, acetone, see 05 tic ether, etc., to which solution there is added a certain amount of castor oil or other suitable similar oil, such that the impregnated sheet'shall have the requisite suppleness and thickness. Good results can be obtained by adding approximately 4.0% of castor Oil to a 2 solution of either collodion or celluloid.

A stencil-sheet produced according to this invention possesses body and need not be 7 moistened before being typ'ed upon, and it can crack, and'even be creased or rumpled without any ink spots getting upon the copies.

The same advantages can Obviously. be obtained, although in a lesser degree, by using two sheets one placed upon the other, the first sheet being simply impregnated with collodion or a solution of celluloid,

whereas the other sheet is simply coated with as paraffin.

Or a single sheet may be used simply impregnated with collodion or a solution of celluloid, and the supporting foundation or underlay being coated with acoat of paraffin. 90

' What I claim is 1. A type-impressible stencil-sheet havin a base such as Japanese Yoshino coated wit asubstance including celluloid and a suitable oi 2. A type-im ressible stencil-sheet having a base such as apanese Yoshino coated with a lsubstance including celluloid and castor o1 3. A type-impressible stencil-sheet having 0 a, base such as Japanese Yoshi n0 coated with 5. A type-imprcssibls sheet having a substance including celluloid, a. suitable a base such as Japanese Yoshino coated with T10 bila-nd a solidifiable fatty material. a substance including collodion modified by 4. Atype-ixn ressible stenciLsheet having camphor, and a suitable oil. a base such as a nese Yosllino coated. with This specification signed this 2211i day of a substance inclu g celluloid a suitable oil September, 1923. 2" afidosolidifiable fatty matenal applied to said sheet on one side thereof; 1 ommm; mm. 

